This invention relates to a method of producing thermally a flow of a working medium, especially for the operation of a turbine or the like.
In steam turbines it is necessary, for achieving a satisfactory efficiency degree, to condense the operation steam tapped from the turbine to liquid phase, which thereafter by a feed pump is recycled to the boiler.
The invention has particularly the object to provide an energy machine in the form of a turbine, which operates with the reaction force from a thermally produced high-speed atomized liquid jet, the steam phase in which is so small that no condenser is required.
The invention is based on the idea, that water, which is heated to a high temperature and a pressure corresponding to the temperature without boiling, is tapped through an outlet passageway to an outflow nozzle of suitable form and size so that the medium flows out to an ambient or low pressure in the form of a very rapid jet of very small droplets, which spray jet has a surprisingly low temperature and also surprisingly is substantially free of steam.
The major part of the heat supplied to the working medium is retrieved in the spray jet as kinetic energy of the droplets, and a very small part of the heat is bound as steam formation heat in the jet.
The inventor has carried out an extensive series of experiments with a simple experimental arrangement. It comprised an electrically heated cylindrical boiler with a vertical axis. The boiler was upwardly provided with a filler opening with screw lock and downwardly with a drain passageway to a governor valve and a horizontally directed outlet nozzle. The boiler was upwardly pivotally suspended on a horizontal shaft, and the nozzle was held by a dynamometer, at which the reaction force of the spray jet could be read directly. A manometer indicated the pressure in the boiler, and a well-calibrated thermometer, one soldered joint of which was immersed in melting ice, indicated the temperature in the mouth of the outlet nozzle.
The drain passageway had a diameter of about 10 mm, and a length of about 70 mm. The smallest cross-section of the nozzle was about 2 mm.sup.2, and its outlet cross-section was 200 mm.sup.2, with a cone angle of about 10.degree..
The boiler held about 1 liter and was at the experiments filled with only about 0.7 liter water, in order to prevent the risk that the boiler would hydraulically burst due to the water expansion at heating.
During a typical experiment heat was supplied until the manometer indicated about 86 bar, which corresponds to a power water temperature of about 300.degree. C.
The opening of the governor valve resulted immediately in a forceful spray jet of atomized water of high speed. For 6-7 seconds, i.e. until the boiler was emptied, an almost constant reaction force of about 100 N from the jet was read. The temperature read in the nozzle aperture was at the same time 35-40 .degree. C. No steam cloud about the jet was observed. By bare hand the temperature about half a meter downstream of the nozzle in the jet was judged to be 30.degree.-35.degree. C. The jet wetted the hand. From data and measured values the outlet spread of the jet was calculated to be about 1000 m/s.
The impulse of the jet from the nozzle can be utilized, for example, for driving a turbine of known type, either as a reaction turbine with the nozzles arranged on the turbine wheel, or as an action turbine with the nozzles fixed in the turbine housing. The invention can be said to be characterized in that the working medium is heated to desired temperature in a closed space at a pressure, which is higher than the steam formation pressure of the working medium at the desired temperature, and that the working medium in liquid phase is tapped and passed to one or more outflow nozzles against lower pressure.
Due to the fact that according to the invention the working medium after the turbine is in liquid phase, it is possible to produce thermally an atomized liquid jet even at low temperatures by a working medium with properties adapted thereto. The heat source can be of known kind. Especially when using a volatile working medium operating at low temperatures, however, it can be the condenser side of a heat pump circuit, which takes up heat at low temperature from a natural heat supply, for example the sea, and emits the heat at higher temperatures to the heat source.